A crash diet is any eating plan that promises rapid weight loss by slashing calories, skipping meals, or banning entire food groups—often to levels that are nutritionally inadequate and hard to sustain.
Definition: what counts as a “crash diet”?
Very low calorie intake, typically below 1,200 kcal/day and often under 800 kcal/day, for days to a few weeks.
Extreme rules such as juice cleanses, “detox” teas, liquid-only plans, or cutting out major food groups (like all carbs or all fats).
Marketing that promises big, fast results (for example, “lose 5–10 kg in 2 weeks”) without a long‑term maintenance plan.
In short, if a diet shocks your system, leaves you constantly hungry or weak, and isn’t something you could follow during normal life, it’s likely a crash diet.
Why crash diets are risky
Metabolic slowdown & rebound gain: Rapid loss can lower your metabolic rate and increase the chance of regaining weight (the “yo‑yo” effect).
Nutrient deficiencies: Severely restricted plans often lack protein, vitamins, and minerals, affecting immunity, skin, hair, nails, and bones.
Muscle loss: The body breaks down muscle for energy when calories and protein are too low.
Gallstones & heart strain: Very‑low‑calorie diets raise gallstone risk and can transiently worsen heart function, especially in people with existing heart issues.
Mental health impact: Restrictive rules can trigger cravings, bingeing, and disordered eating patterns.
A safer approach to weight loss
Aim for gradual loss (about 0.5–1 kg per week) with a moderate calorie deficit.
Prioritize protein, fiber, and healthy fats to stay full and protect muscle.
Include regular movement (walking after meals, strength training) and consistent sleep.
Choose plans you can maintain during work, travel, and family meals—not just for a “challenge week.”
